Epoxy resins from bisphenols of 3, 9-divinyl spirobi



United States Patent 3,401,147 EPOXY RESINS FROM BISPHENOLS 0F 3,9-DI-VINYL SPIROBI (m-DIOXANES) Samuel G. Smith, Jr., Hillsborough Township,Ralph F. Sellers, Somerset, and Allison S. Burhans, Millington, N.J.,assignors to Union Carbide Corporation, a corporation of New York NoDrawing. Continuation-impart of application Ser. No. 269,790, Apr. 1,1963. This application Oct. 17, 1966, Ser. No. 586,931

9 Claims. (Cl. 260-47) This is a continuation-in-part of Ser. No.269,790, filed on Apr. 1, 1963 and now abandoned.

This invention relates to novel epoxy resins and more particularly tothose derived from bisphenols of 3,9- divinyl spirobi (m-dioxanes).

Epoxy resins derived from bisphenol A, i.e.,2,2-bis(4-hydroxyphenyl)propane have found many useful applications whencured or hardened with appropriate curing agents. However, despite themany advantages of the prior art epoxy resins they are limited, wheretoughness, as demonstrated by high impact strength, for example isrequired.

It has now been discovered that cured epoxy resins derived frombisphenols of 3,9-divinyl spirobi (m-dioxane) have superior toughness ascompared with bisphenol A epoxy resins.

The bisphenols of 3,9-divinyl spirobi (rn-dioxane) have superiortoughness as compared with bisphenol A epoxy resins.

The bisphenols of 3,9-divinyl spirobi (m-dioxane) have the structurewherein R is hydrogen, alkyl having from 1 to 6 carbon atoms inclusiveor halogen, i.e., a chloro, bromo, fluoro or iodo group.

The epoxy resins of the instant invention can be prepared by reactingthe bisphenol of 3,9-divinyl spirobi (m-dioxane) with an epihalohydrin,preferably epichlorohydrin, in the presence of aqueous alkali metalhydroxide and an organic solvent such as an aliphatic alcohol andketone.

3,401,147 Patented Sept. 10, 1968 other conventional hardeners can heused if desired. Examples of other suitable curing agents includeprimary and secondary amines such as ethylene diamine, diethylenetriamine, a-methyl benzyl dimethylamine, tridimethyl amino methylphenol, and the like; anhydrides such as hexahydrophthalic anhydride,pyromellitic anhydride, chlorendic anhydride and the like; andpolyamides such as condensation polymers of dimerized and trimerizedvegetable oil unsaturated fatty acids and aryl or alkyl polyamines andthe like. Bisphenols of in the presence of acidic alkylation catalyst bythe reaction of phenol with 3,9-divinyl spirobi (m-dioxane) on thepresence ofacidic alkylation catalyst by the method which includes thesteps of forming a mixture of the phenol with from 0.01 to 10 percent byWeight based on the total amount of phenol and 2,9-divinyl spirobi(m-di0xane) of a phosphoric acid catalyst, adding to the mixtureincremental amounts of 3,9-divinyl spirobi (m-dioxane) up to a molarratio of phenol to 3,9-divinyl spirobi (m-dioxane) of 2:1 and separatingthe bisphenol product.

The reaction proceeds as follows:

The point of attachment of the phenyl moieties can be either ortho orpara to the phenolic hydroxyl. The bisphenol can have a cis or transconfigurationpThe point of attachment of the phenyl moiety to the3,9-divinyl spirobi (m-dioxane) can be either on the ,8 carbon atoms (asshown) or on the or carbon atoms. Although the skeletal structure mayvary somewhat, the product obtained by the present method is definitelythe bisphenol of 3,9-divinyl spirobi (m-dioxane) as indicated by closeagreement of actual and theoretical values for molecular weight andhydroxyl content.

Acidic alkylation catalysts suitable for preparation of The epoxy resinsof the present invention have the bisphenols of 3,9-divinyl spirobi(rn-dioxane) include general formula acidic ion exchange resinsidentified 'by-such trademarks wherein n has a value of 0 to 10 andpreferably from 0 to 3 and Bis PA represents the structure wherein R isas defined as above.

The preferred curing agents or hardeners for use with the epoxy resinsof the present invention are 4,4'-methylene dianiline and metaphenylenediamine used in approximately stoichiometric amounts although asAmberlite XE-lOO (Rohm and Haas), Dowex 50-X-4 (Dow Chemical Co.) andthe like, and acidic catalysts. The latter are exemplified but notlimited by such compounds as phosphoric acid, citric acid, oxalic acid,sulfuric acid and the like.

The amount of acidic alkylation catalyst employed in the preparation ofthe bisphenol is not narrowly critical. Concentrations in the reactionmixture of 0.01 to 10 percent and preferably 0.4 to 2.0 per-cent byweight, based on the total weight of phenol and 3,9-divinyl spirobi(m-dioxane) present are generally employed.

By the term phosphoric acid catalyst is means phosphoric acid per se,i.e., orthophosphoric acid (H PO as well as pyrophosphoric acid (H P Oand compounds which are capable of forming orthophosphoric acid such asphosphoric acid anhydride or phosphorus pentoxidc (P and metaphosphoricacid (H1 0 It is preferred that the acid be present in the reactionmixture in a relatively concentrated form, e.g., 85 percent phosphoricacid but the presence of greater amounts of water has not been observedto unduly interfere with the reaction. The use of 50 percent by weightand above aqueous solution of phosphoric acid is preferred. Mixtures oforthophosphoric acid and phosphorus pentoxide can also be used.

Phenols which can be alkylated with 3,9-divinyl spirobi m-diox ane) toform the bisphenols thereof useful in this invention are hydroxysubstituted aryl compounds having a replaceable hydrogen attached to aring carbon atom in a position other than meta, i.e., either ortho orpara to a phenolic hydroxyl. Thus the term phenol includes mono-nuclear,substituted and unsubstituted hydroxyaryl compounds. A replaceablehydrogen as the term is used in the present specification and claims is(1) a hydrogen which is attached to a carbon atom which is not impededfrom reacting with 3,9-divinyl spirobi (mdioxane) by the spatialarrangement of nearby atoms forming a part of the same molecule, i.e.,is sterically unhindered and (2) is electronically unhindered, i.e., isnot limited in activity by the presence, in other positions on thephenolic ring, of substituents tending to attract the ortho and parahydrogen more strongly to the phenolic ring, e.g., nitro groups. Amongthe phenols having replaceable hydrogens in the positions ortho and parato a phenolic hydroxyl, some of those deserving of special mention are:hydroxy substituted benzenes, e.g., phenol, catechol, pyrogallol,resorcinol, phloroglucinol, and unsymmetrical trihy-droxy substitutedbenzenes; substituted phenols having in the meta positions, orthopositions or para position, providing at least one of the ortho positionor the para position is unsubstituted, one or more ortho or paradirecting substituents such as alkyl groups, aryl groups, alkarylgroups, halogen groups, i.e., fluoro, chloro, bromo, and iodo, alkoxygroups and aryloxy groups. Preferred as substituents in the abovecompounds are straight and branched chain alkyl and aralkyl groupshaving from 1 to carbon atoms, particularly lower alkyl substituents,i.e., having from 1 to 6 carbon atoms. Among the substituted phenolsthose deserving of special mention are the cresols, xylenols, guiacol,4- ethylresorcinol, S-methylresorcinol, 4-propylresorcinol, carvacrol,methylphenol, ethylphenol, butylphenol, octylphenol, dodecylphenol,eicosylphenol, tricontylphenol, and tetracontylphenol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2-ethyl-4-propylphenol,2,5-dimethylphenol, 2- ethyl-4methylphenol, 2,4-diethylphenol,2-methyl,4-butylphenol, Z-ethyl-S-methylphenol,2-methyl-5-isopropylphenol, 2-propyl-5-methylphenol,2-isopropyl-5-methylphenol, 2,6-dimethylphenol, 2-methyl-6-ethylphenol,2,6-diethylphenol, 2-methyl-6-propylphenol, 3,4-dimethylphen01,3-methyl-4-ethylphenol, 3,5-dimethylphenol, 3,5-diethylphenol,2-chloro-4-methylphenol, 2-ethyl-4-chlorophenol,3-chloro-3-methylphenol, 2,3,4-trimethylphenol, 2,3,5-trirnethylphenol,2,4-dimethyl 5 ethylphenol, 2- ethyl-4,5-dimethylphenol,2,4-diethyl-5-methylphenol, 3,4, S-trimethylphenol and higher alkylphenols.

In preparing the bisphenols, 3,9-divinyl spirobi (m-dioxane) is added toa mixture of the phenol and phosphoric acid catalyst. The ratio ofphenol to 3,9-divinyl spirobi (rn-dioXane) is not critical provided itis at least 2:1 but higher ratios such as 5:1 to :1 by weight, with 10:1by weight being preferred, are ordinarily used.

The addition of 3,9-divinyl spirobi (m-dioxane) is incremental, i.e.,dropwise. It has been found that heating a mixture containing all ofboth the phenol and 3,9- divinyl spirobi (m-dioxane) reactants producesresinous products having molecular weights over 1000. The reactionmixture, over the course of incremental addition, is held at an elevatedtemperature, e.g., C. to 100 C. with pressure as necessary, andpreferably at between 4 35 and C. until reaction is substantiallycomplete, usually several hours at the preferred temperatures.

Solvents can be used in the bisphenol forming reaction vessel ifdesired. Typical solvents are inert organic liquids such ashydrocarbons, ketones, and halogenated hydrocarbons.

The product can be isolated by means conventional in the art. Theresidue can be dissolved in a solvent such as methylethyl ketone ortoluene and recrystallized, whereupon filtration then separates thebisphenol from the reaction mixture.

The invention is further defined by the examples which follow in whichall parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 To a five-liter three-necked flask equipped with mechanicalstirrer, thermometer, reflux column and dropping funnel there was added10 moles of phenol and 4.6 grams [0.4% based on phenol and 3,9-divinylspirobi (m-dioxane)] of a phosphoric acid catalyst comprising H PO +P Ofor an equivalent of percent H PO With vigorous agitation the charge wascooled to 35-45 C. and one mole of 3,9-divinyl spirobi (m-dioxane)dissolved in toluene was added dropwise over a period of 150 minutes.During the addition, the reaction exotherm was controlled to maintainthe temperature of the reaction mixture between 35 and 45 C. for anadditional 18-22 hours. The reaction mass was neutralized to pH 5-6 byaddition of a 50 percent aqueous solution of sodium hydroxide. The crudebisphenol of 3,9-divinyl spirobi (m-dioxane) was isolated bydistillation to a final pot temperature of 290 C. at a pressure of 10mm. Hg. The crude bisphenol which was the residue product was separatedfrom the salts of neutralization by dissolution in methyl filtration andevaporation of the toluene. There was obtained a light coloredsemi-grindable material with C. tripod flow of 3536 seconds.

The 150 C. tripod flow test is a rapid method for checking product toproduct resin structural uniformity and is performed as follows:

A brass rod 4 /2 x weighing 69.7 g. is placed vertically within atripod-mounted tube, ID. with the bottom of the rod resting on acylindrical pellet of the test resin, OD. and /8 in length placed in thebottom of the tube. The tripod is mounted on a hot plate held at 150 C.with the bottom of the pellet contiguous with the surface of the hotplate, and the bottom of the tube elevated above the hot plate surface.As the resin pellet melts and flows out, the brass rod resting on itdrops. The time in seconds required for the brass rod to drop /2" isrecorded as the tripod flow time.

EXAMPLES 25 Bisphenol product-s having essentially the same propertieswere obtained by repeating Example 1 with the exception that thephosphoric acid catalyst was replaced by dried Dowex-S0X4, citric acid,oxalic acid or sulfuric acid.

EXAMPLE 6 The Bisphenol prepared as in Example 1 was epoxidized bycharging 640 g. of this product to a 3 liter 4-ncck, round-bottom flaskfitted with an agitator, thermometer, dropping funnel and a condenserwhich could be used either for reflux or distillation, together with1184- g. of epichlorohydrin and 320 g. of ethanol. The charge was heatedto reflux (86 C.) and then g. of additional ethanol was added to theflask along with 145 g. of methylethyl ketone.

The temperature of the reactants was adjusted to 6065 C. and 50% aqueoussodium hydroxide was added slowly through the dropping funnel accordingto the following schedule:

31 g. over a 60 minute period 31 g. over the next 30 minutes 217 g. overthe next 60 minutes 31 g. over the next 60 minutes The dropping funnelwas rinsed into the reaction flash with 25 g. of water and the chargewas stirred for 20 minutes at 60-65 C.

The condenser was adapted for vacuum distillation, and unreactedepichlorohydrin, ethanol, methylethyl ketone and water distilled offover a period of 1.75 hours under a gradually diminishing pressure untilthe final conditions were 135 C. pot temperature at about 50 mm. Hgpressure.

The reactor residue was dissolved in 960 g. of methylisobutyl ketone andwashed with 96% of hot water which dissolved salts and residual alkali.

The washed residue was transferred to a liter separatory funnel and theaqueous wash layer removed. The organic layer (epoxy resin solution) waswashed twice more with 960 g. portions of hot water. The pH of the thirdwash was 6.0.

The solvent was removed from the epoxy resin solution by vacuumdistillation.

Live steam was bubbled through the molten epoxy resin at 135-140 C.under a pressure of 25-50 mm. Hg for minutes. Then residual water wasremoved by vacuum distillation. The epoxy resin of the bisphenol of3,9-divinyl spirobi (m-dioxane) cooled to a solid mass at roomtemperature having an epoxy assay of 339 grams/ gram equivalent.

This product when cured with a stoichiometric amount of 4,4-methylenedianiline at 80 C. for 3-4 hours followed by heating at 160 C. for 4hours afforded a casting having the following physical properties.

Izod impact strength (ASTM D-256-56) ft./lbs./in. 1.34 Tensile modulus(ASTM D-638-58T) ..p.s.i 425,000 Tensile strength (ASTM D63858T) p.s.i11,400 Flexural modulus (ASTM D-790-58T) p.s.i 462,000 Flexural strength(ASTM D-790-58T) p.s.i 17,100

Control A A commercial epoxy resin based on bisphenol A having an epoxyassay of 192 g./g. equivalent was cured with a stoichiometric amount of4,4-methylene dianiline at 80 C. for 3-4 hours followed by heating at160 C. for 4 hours as a Control for comparison with the cured epoxyproduct. The casting had the following properties:

Izod impact strength ft./lbs./in 0.31

Tensile modulus p.s.i 405,000

Tensile strength p.s.i 10,300

Flexural modulus p.s.i 418,000

Flexural strength p.s.i 16,000

EXAMPLE 7 Izod impact strength ft./1bs./in 1.50

Tensile modulus p.s.i. 416,000

Tensile strength p.s.i 10,500

Flexural modulus p.s.i 499,000

Flexural strength p.s.i 18,900

EXAMPLE 8 An epoxy resin of the bisphenol of 3,9-divinyl spirobi(m-dioxane) prepared as described in Example 6 and having an epoxy assayof 330 g./ g. equivalent was cured with metaphenylene diamine at 80 C.for 3-4 hours followed by heating at 160 C. for 4 hours. The resultantcasting had the following properties:

Izod impact strength ft./lbs./in 0.54

Tensile modulus p.s.i 533,000

Tensile strength p.s.i 13,600

Flexural strength p.s.i 19,200

Control B As a control B for comparison with the cured epoxy resin ofExample 8 a commercial epoxy resin based on bisphenol A and having anepoxy assay of 183 g./g. equivalent was cured with metaphenylene diamineat C. for 3-4 hours followed by heating at C. for 4 hours. The castinghad the following properties.

Izod impact strength ft./lbs./in 0.26 Tensile modulus p.s.i 458,000Tensile strength p.s.i 12,900 Flexural strength p.s.i- 16,400

It can be seen from the above examples and controls that the cured epoxyresin from the bisphenol of 3,9-divinyl spirobi (m-dioxane) have asurprisingly greater toughness than the conventional, commerciallyavaiable bisphenol A based epoxy resins. This unexpected improvement intoughness can be viewed as due to the replacement of the isopropylidenemoiety of bisphenol A by the 3,9-divinyl spirobi (m-dioxane) moiety.

EXAMPLES 9-12 wherein n has a value of 0 to 10 and Bis PA represents thestructure wherein R is selected from the group consisting of hydrogen,alkyl having from 1 to 6 carbon atoms and halogen.

2. The epoxy resin of claim 1 hardened with an approximatelystoichiometric amount of an epoxy resin curing agent selected from thegroup consisting of primary amines, secondary amines, anhydrides, andpolyamides.

3. The hardened epoxy resin of claim 2 wherein the curing agent is aprimary amine.

4. The hardened epoxy resin of claim 3 wherein the curing agent is4,4'-mcthylene dianiline.

' 5. The hardened epoxy resin of claim 3 wherein'the curing agent ismetaphenylene diamine.

6. The epoxy resin of claim 1 wherein n has a value of 0 to 3.

7. The epoxy resin of claim 1 wherein n has a value of 0.

8. The epoxy resin of claim 1 wherein R is hydrogen.

9. The epoxy resin of claim 1 wherein R is methyl.

8 References Cited UNITED STATES PATENTS 2,841,595 7/1958 .Pezzaglia260-47 2,915,501 12/1959 Guest et a1 260340.7 3,128,255 4/1964 McGary eta1 26047 WILLIAM H. SHORT, Primary Examiner.

T. D. KERWIN, Assistant Examiner.

1. THE EPOXY RESIN HAVING THE GENERAL FORMULA